ACETONE OILS 17
7. Quantitative Determination.—Messinger's method is used (see
Commercial pure acetone should be colourless and neutral, of D not exceeding
0-800 at 15°, should distil to the extent of at least 95% below 58°, and should
mix in all proportions with water. It should leave no residue on evaporation,
should not decolorise permanganate, and should not contain more than 0-1%
These residues from the purification and rectification of crude acetone
consist mainly of various higher ketones (methyl ethyl ketone, methyl
propyl ketone) and form more or less intensely yellow liquids of peculiar
and disgusting odour, acrid, burning taste, D 0-828-0-842, b.pt. very variable
according to the quality (75° to 110° or even higher) ; they are only partly
soluble in water but are miscible in all proportions with alcohol. The
tests made include distillation, solubility in water, acetone content and
1. Distillation.—A 100 c.c. flask, identical with that used for the
distillation of pyridine bases (see chapter on Tar and its Products), is used,
the distillation being arranged so that the liquid passes over drop by drop ;
the different fractions corresponding with each 5° C. are collected in graduated
cylinders or tubes.
2. Solubility in Water.—In a 100 c.c. graduated cylinder are placed
20 c.c. of the oil and 20 c.c. of water. After vigorous shaking, the liquid
is allowed to stand until two distinct layers are formed, the number of c.c.
of oil dissolved being noted. Sixty c.c. of water are then added and the
volume of oil dissolved determined as before. The results obtained are
multiplied by 5 and expressed thus :
(a] Solubility in an equal volume of water : . . . c.c. per 100 of the oil.
(b) Solubility in four volumes of water : . . . c.c. per 100 of the oil.
3. Ketone Content.—In this determination, the same liquids are used
as in the determination of acetone in crude methyl alcohol, and the same
procedure is followed (see Methyl Alcohol, Determination of Acetone).
Ten c.c. of the oil are made up to 1000 c.c. with water in a graduated flask,
which is shaken so as to extract the soluble part of the oil as far as possible.
Ten c.c. of the liquid (corresponding with o-i c.c. of the oil) are placed in a
bottle holding 300-400 c.c. and provided with a ground stopper; 20 c.c.
of solution a are then added and 50 c.c. of solution c run in gradually from a
burette. The bottle is tightly stoppered, well shaken and then left for an
hour with occasional agitation. Twenty c.c. of solution b are next added
and the liquid titrated with thiosulphate solution d in presence of starch
Thus, by difference, the quantity of iodine, a, absorbed by the oil is
obtained, the formula,
% =2^JL.x 1000,
giving the weight of ketones, expressed as methyl ethyl ketone, in 100 c.c.
A.c. 2dness and contain moderate proportions of calcium